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Purging (manufacturing)

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Purging (manufacturing)
Before and after purging image of injection molding machine screw
Process typeCleaning process of Injection moulding

Purging is a cleaning process of injection molding to clean thermoplastics molding machines and extruders. This process is very important as a virgin resin cannot effectively remove previous resin residuals from the previous run.[1]

Method

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Below are the major steps for purging-[2]

  • Turn off the material flow in the injection molding machine
  • Turn off the colorant flow which is added or applied in order to change the colour of a material
  • Maintain existing process settings and continue manufacturing plastics parts
  • When last part is completed, set the nozzle retraction mode
  • Clean hopper and colorant blender (whichever necessary)
  • Load any commercial purging material or new material to be used into hopper feed zone
  • Clean nozzle and sprue bushing by making few shots
  • Continue purging until most of the commercial purging material is out of the hopper
  • Feed at least one injection capacity of the next production resin to rinse out any residuals
  • Start the next production with new resin


References

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  1. ^ "Tips of the trade: Purging troubleshooting for injection molding". Plastics Today. August 23, 2010. Retrieved November 18, 2020.
  2. ^ "Follow These Tips to Power Up Your Purging Process". Plastics Technology. Retrieved November 18, 2020.